ACE2通过下调AT1R和ERK1/2的磷酸化而抑制平滑肌细胞的增殖

目的 探讨血管紧张素转换酶2(ACE2)对血管紧张素Ⅱ1型受体(AT1R)和细胞外基质激酶(ERK)1/2磷酸化水平及细胞增殖的影响.方法 荧光显微镜下观察绿色荧光蛋白(GFP)的表达;将载有ACE2基因慢病毒表达载体(Lentiviral-ACE2)以感染复数为10(MOI=10)感染平滑肌细胞不同时间(24、48、72、96 h);采用CCK-8法检测平滑肌细胞增殖;Western blot检测ACE2、AT1R及ERK1/2磷酸化水平.结果 目的 蛋白GFP表达量明显增加,慢病毒ACE2的表达量成时间依赖性增加,并且在96 h时蛋白表达量较对照组和空载体组明显升高,(1.22±0.06 vs 0.53±0.03和0.53±0.09,P<0.05,n=4);AngⅡ(10-7 mol·L-1)可以促进平滑肌细胞的增殖,ACE2能够抑制AngⅡ诱导的平滑肌细胞增殖(0.53±0.10 vs 0.68±0.03,P<0.05,n=5);AngⅡ(10-7 mol·L-1)作用平滑肌细胞12 h后AT1R明显上调,同时ACE2明显抑制AngⅡ诱导的AT1R的上调(0.34±0.01 vs 0.73±0.07,P<0.05,n=4); ACE2能够明显抑制AngⅡ诱导的ERK1/2的磷酸化水平 (0.43±0.06 vs 0.71±0.08,P<0.05,n=4).结论 ACE2可以通过下调AT1R和/及ERK1/2 的磷酸化水平而抑制平滑肌增殖,提示ACE2的过表达具有血管保护作用.     

ACE2小干扰RNA对平滑肌细胞AT1受体蛋白表达及其下游信号通路的影响

目的研究ACE2 siRNA干预SD大鼠平滑肌细胞(vascular smooth muscle cells,VSMCs)后,探讨ACE2对血管紧张素Ⅱ1型受体(AngⅡtype 1 receptor,ATlR)蛋白表达、ERK1/2、STAT3蛋白磷酸化水平的影响。方法(1)用脂质体法将含有ACE2基因的质粒DNA及si-ACE2转染到各对应干预组VSMCs;(2)Western blot检测各组细胞ACE2、AT1R蛋白表达水平以及p-ERK1/2、p-STAT3蛋白的磷酸化水平。结果(1)对比空白对照组、GFP组、脂质体组,si-ACE2组、AngⅡ组ACE2蛋白表达明显降低,而AT1R蛋白表达和p-ERK1/2、p-STAT3蛋白磷酸化水平明显增加(P<0.05);(2)分别对比AngⅡ组和AngⅡ+ACE2组,AngⅡ+si-ACE2组和AngⅡ+ACE2+si-ACE2相应的ACE2蛋白表达均降低,而AT1R蛋白表达、p-ERK1/2、p-STAT3蛋白磷酸化水平均增加(P<0.05)。结论ACE2 siRNA和AngⅡ均能抑制ACE2蛋白的表达,且两者对ACE2起协同抑制作用;ACE2蛋白表达的减少能上调AT1受体蛋白表达,同时提高其下游信号通路ERK1/2、STAT3蛋白磷酸化水平。     

厄贝沙坦抑制大鼠平滑肌细胞AT1R及其下游信号通路

目的本研究目的是利用厄贝沙坦、血管紧张素Ⅱ(AngⅡ)干预平滑肌细胞,阐明血管紧张素Ⅱ受体阻滞剂(ARB)对血管紧张素Ⅱ1型受体(AT1R)表达及其下游信号通路的影响。方法利用Western Blot技术,研究厄贝沙坦、血管紧张素Ⅱ干预平滑肌细胞后对细胞AT1受体蛋白表达及其下游信号通路-细胞外信号调节激酶1/2(ERK1/2)和信号转导子和转录激活子3(STAT3)蛋白磷酸化水平的影响。结果研究发现厄贝沙坦能显著地抑制AngⅡ诱导的AT1受体蛋白表达(0.208±0.022 vs 0.997±0.131,P<0.01)及下游信号通路中的ERK1/2蛋白磷酸化(0.055±0.007 vs 0.103±0.020,P<0.01)、STAT3蛋白磷酸化(0.162±0.010 vs 0.758±0.054,P<0.01)。结论这些研究结果表明厄贝沙坦抑制AT1R和下游的ERK1/2及STAT3信号通路,从而抑制AngⅡ诱导的平滑肌细胞增殖等,发挥控制血压、防治心脑血管疾病作用。     

丹参酮ⅡA磺酸钠对AngⅡ诱导的心肌细胞肥大反应中磷酸化细胞外信号调节激酶1/2的作用

目的从细胞外信号调节激酶1/2(ERK1/2)激活角度研究丹参酮ⅡA磺酸钠(sodium tanshinoneⅡ Asulfonate,STS)对血管紧张素Ⅱ(angiotensinⅡ,AngⅡ)诱导的心肌肥大反应中的作用。方法培养新生大鼠心肌细胞,考马斯亮蓝法测定心肌细胞蛋白含量、[3H]-亮氨酸参入法测定蛋白合成速率作为心肌肥大指标;用免疫荧光标记法和Western blot测定磷酸化ERK1/2蛋白(p-ERK1/2)表达。结果(1)AngⅡ(1μmol·L-1)处理24h,心肌细胞[3H]-亮氨酸参入率、蛋白含量明显增加,STS能明显抑制AngⅡ介导心肌细胞[3H]-亮氨酸参入率、蛋白含量的增加;(2)AngⅡ刺激心肌细胞可见胞核内出现磷酸化ERK1/2荧光染色,丹参酮ⅡA可阻断AngⅡ引起的ERK1/2活化、入核过程;(3)用AngⅡ(1μmol·L-1)处理心肌细胞5min,磷酸化ERK1/2蛋白(p-ERK1/2)表达即开始增加,10min左右时最明显。以AngⅡ(1μmol·L-1)处理心肌细胞10min,磷酸化ERK1/2蛋白(p-ERK1/2)表达为标准,预先以STS(2,10,50μmol·L-1)处理心肌细胞30min,发现STS可明显抑制AngⅡ诱导的心肌细胞磷酸化ERK1/2蛋白表达;(4)预先以不同浓度STS处理心肌细胞30min,发现STS对AngⅡ诱导的心肌细胞磷酸化ERK1/2蛋白表达的抑制作用存在剂量依赖性。结论STS可以抑制AngⅡ诱导的心肌肥厚,其机制与抑制磷酸化ERK1/2表达有关。     

苯那普利与厄贝沙坦对心衰大鼠心室重构过程中AngⅡ受体及ACE2的影响

目的探讨苯那普利、厄贝沙坦及两者联合用药对心衰大鼠心室重构过程中心肌血管紧张素Ⅱ1型受体(AT1R)、2型受体(AT2R)及ACE2蛋白表达的影响。方法采用大鼠腹主动脉缩窄法造成压力负荷性心肌肥厚致心力衰竭模型。苯那普利或(和)厄贝沙坦连续给药8wk,检测血流动力学参数、心脏指数、心肌和血浆AngⅡ含量、心肌中AT1R、AT2R和ACE2蛋白的表达情况。结果模型组心脏指数、LVEDP、血浆和心肌AngⅡ的含量及心肌AT1R、AT2R和ACE2蛋白的表达明显升高;各治疗组心脏指数、LVEDP明显下降;苯那普利组血浆和心肌AngⅡ的含量降低,厄贝沙坦组心肌AT1R蛋白的表达明显下降而AT2R和ACE2蛋白的表达明显升高,联合应用具有协同作用。结论联合应用苯那普利和厄贝沙坦对改善心衰大鼠心室重构具有协同作用,可能与AngⅡ和AT1R的下调而AT2R和ACE2的上调有关。     

甘草次酸抑制K562细胞增殖的机制的实验研究

目的:探讨甘草次酸(GA)抑制K562细胞增殖的机制.方法:对体外培养的K562细胞体系,采用MTT,放免,免疫组织化学的测定方法.结果:K562细胞抑制率与GA浓度及用药后培养时间呈正相关性.GA作用48 h后细胞上清液中血管紧张素Ⅱ(AngⅡ)含量明显上升.K562细胞中检测到AngⅡ 1型受体(AT1R)及2型受体(AT2R)蛋白的表达,但GA对其表达的影响无统计学意义.结论:GA可能通过抑制AngⅡ与AT1R的结合而抑制肿瘤细胞的增殖.     

血管紧张素Ⅱ和缬沙坦对血管内皮细胞AT1/AT2及eNOS表达的调节作用

目的：研究缬沙坦在血管内皮细胞中对血管紧张素Ⅱ(AngⅡ)受体Ⅰ型(AT1)和Ⅱ型(AT2)、一氧化氮合酶(eNOS)的表达和一氧化氮(NO)生成的影响。方法：使用人脐静脉内皮细胞系ECV-304(HUVECs)，分为对照组、AngⅡ组、缬沙坦组和AngⅡ加缬沙坦组，作用不同时间，检测AT1／AT2的mRNA和蛋白表达、eNOS的蛋白表达和NO的生成。结果：在HUVECs细胞中未检测到AT2的蛋白表达，AngⅡ、缬沙坦均显著抑制细胞中AT1的mRNA和蛋白表达，且缬沙坦呈明显的剂量依赖效应，AngⅡ作用36h显著抑制NO的生成而合用缬沙坦可明显逆转该效应。结论：在HUVECs中缬沙坦可通过自身的结合下调AT1，并能逆转AngⅡ长时间作用对NO生成的抑制作用，提示缬沙坦可改善血管内皮细胞的功能。     

血管紧张素Ⅱ和缬沙坦对血管内皮细胞AT_1/AT_2及eNOS表达的调节作用

目的研究缬沙坦在血管内皮细胞中对血管紧张素Ⅱ(AngⅡ)受体I型(AT1)和Ⅱ型(AT2)、一氧化氮合酶(eNOS)的表达和一氧化氮(NO)生成的影响。方法使用人脐静脉内皮细胞系ECV304(HUVECs),分为对照组、AngⅡ组、缬沙坦组和AngⅡ加缬沙坦组,作用不同时间,检测AT1AT2的mRNA和蛋白表达、eNOS的蛋白表达和NO的生成。结果在HUVECs细胞中未检测到AT2的蛋白表达,AngⅡ、缬沙坦均显著抑制细胞中AT1的mRNA和蛋白表达,且缬沙坦呈明显的剂量依赖效应,AngⅡ作用36h显著抑制NO的生成而合用缬沙坦可明显逆转该效应。结论在HUVECs中缬沙坦可通过自身的结合下调AT1,并能逆转AngⅡ长时间作用对NO生成的抑制作用,提示缬沙坦可改善血管内皮细胞的功能。     

氯沙坦抑制ROS/ERK1/2信号途径减轻AGEs诱导的大鼠脑血管平滑肌细胞增殖

目的探讨果糖制备的糖基化终末产物(AGEs)对大鼠脑基底动脉血管平滑肌细胞(BASMC)的增殖以及氯沙坦对增殖的影响和机制。方法培养大鼠脑基底动脉血管平滑肌细胞,用CCK8法测定不同浓度(1,5,10μmol/L)氯沙坦对果糖制备的AGEs(200mg/L)预处理48h诱导血管平滑肌细胞增殖的影响。用western blotting检测AGEs以及氯沙坦处理后对ERK蛋白表达影响。结果 AGEs刺激血管平滑肌细胞增殖(0.827±0.069比0.364±0.052,P<0.01)。给予氯沙坦(5,10μmol/L)后,细胞增殖明显下降(0.658±0.064和0.381±0.058比0.827±0.069,P<0.01)。AGEs还使平滑肌细胞内活性氧簇(ROS)生成增多,并显著增加ERK1/2蛋白表达,氯沙坦则明显抑制ROS和ERK1/2蛋白水平。结论果糖制备的AGEs诱导脑基底动脉血管平滑肌细胞增殖,氯沙坦可能通过阻断AT1受体而抑制ROS和ERK1/2表达,减少平滑肌细胞的异常增殖。     

淡豆豉异黄酮对增殖血管平滑肌细胞JAK2/STAT3信号转导通路的影响

目的探讨淡豆豉异黄酮对血管紧张素Ⅱ(angiotensin Ⅱ,AngⅡ)诱导大鼠血管平滑肌细胞(vascular smooth muscle cell,VSMC)增殖及Janus激酶2-细胞信号转导及转录活化因子3(JAK2/STAT3)信号通路的影响。方法建立AngⅡ诱导VSMC增殖模型,MTT法检测VSMC增殖活性;RT-PCR法检测AngⅡ1型受体(angiotensin Ⅱreceptor1,AT1R)mRNA表达;Westernblot法检测JAK2/STAT3信号通路蛋白JAK2,STAT3及其磷酸化表达水平。结果100、200μg·L-1淡豆豉异黄酮可明显抑制AngⅡ诱导的VSMC增殖,并明显下调AT1R mRNA表达水平;200μg·L-1淡豆豉异黄酮可明显下调磷酸化JAK2、磷酸化STAT3的表达。结论淡豆豉异黄酮可抑制AngⅡ诱导的VSMC增殖,其机制可能与下调AT1R表达,阻断JAK2/STAT3信号通路的磷酸化有关。     

Salusin-β对血管平滑肌细胞增殖的作用及其机制研究

目的研究新的内源性活性肽salusin-β对血管平滑肌细胞(VSMCs)增殖的影响及其作用机制。方法原代培养大鼠主动脉VSMCs,MTT法测定不同浓度salusin-β(0.1、1、10nmol.L-1)对VSMCs增殖的影响;Westernblot法测定p-ERK1/2蛋白表达;RT-PCR测定c-myc、c-fos基因表达。结果与对照组相比,salusin-β明显刺激大鼠VSMCs增殖,增加p-ERK1/2蛋白表达,促进c-myc、c-fos基因表达。结论Salusin-β促进大鼠VSMCs增殖可能与激活ERK1/2途径有关。     

Inhibition of vascular smooth muscle cell growth by angiotensin type 2 receptor stimulation for in vitro organ culture model

Recent data suggest that AT2 receptors in smooth muscle cells (VSMCs) of adult vessels may counterbalance AT1 receptor activity by inhibiting cell growth. The role of AT2 receptors in VSMC proliferation was investigated by using an in vitro organ culture model in which the sprouting of tubular structures was assessed. In preparations with endothelium, tubular growth was unaffected by angiotensin II (Ang II) but was inhibited by 50 +/- 9% by losartan and was increased by 110 +/- 15% by the AT2 antagonist PD123177. In endothelium-deprived preparations, growth inhibition (-49.1 +/- 0.5%) was observed when angiotensin II was added together with losartan 1 microM, whereas stimulation (59.8 +/- 14%) was induced by angiotensin II with 1 microM PD123177. In cultured VSMCs angiotensin II slightly promoted growth that was inhibited by losartan but was unaffected by PD123177. AT1a, AT1b, and AT2 mRNA expression was demonstrated in cells isolated from tubular structures grown from intact and endothelium-deprived rings, but only AT1a and AT1b mRNA was detected in cultured VSMCs. In conclusion, this paper proposes an in vitro organ culture model in which the expression of AT2 receptors in VSMCs is preserved and demonstrates AT2 receptor-mediated inhibition of VSMC proliferation in adult vessels.     

Platonin inhibited PDGF-BB-induced proliferation of rat vascular smooth muscle cells via JNK1/2-dependent signaling

Aim:

To examine the inhibitory actions of the immunoregulator platonin against proliferation of rat vascular smooth muscle cells (VSMCs).

Methods:

VSMCs were prepared from the thoracic aortas of male Wistar rats. Cell proliferation was examined using MTT assays. Cell cycles were analyzed using flow cytometry. c-Jun N-terminal kinase (JNK)1/2, extracellular signal-regulated kinase (ERK)1/2, AKT, and c-Jun phosphorylation or p27 expression were detected using immunoblotting.

Results:

Pretreatment with platonin (1–5 μmol/L) significantly suppressed VSMC proliferation stimulated by PDGF-BB (10 ng/mL) or 10% fetal bovine serum (FBS), and arrested cell cycle progression in the S and G₂/M phases. The same concentrations of platonin significantly inhibited the phosphorylation of JNK1/2 but not ERK1/2 or AKT in VSMCs stimulated by PDGF-BB. Furthermore, platonin also attenuated c-Jun phosphorylation and markedly reversed the down-regulation of p27 expression after PDGF-BB stimulation.

Conclusion:

Platonin inhibited VSMC proliferation, possibly via inhibiting phosphorylation of JNK1/2 and c-Jun, and reversal of p27 down-regulation, thereby leading to cell cycle arrest at the S and G₂/M phases. Thus, platonin may represent a novel approach for lowering the risk of abnormal VSMC proliferation and related vascular diseases.     

碘化N-正丁基氟哌啶醇抑制机械损伤诱导的血管平滑肌细胞增殖的作用及机制

目的探讨碘化N-正丁基氟哌啶醇(F2)对机械损伤所致血管平滑肌细胞(VSMCs)增殖的抑制作用及其机制。方法原代培养大鼠胸主动脉VSMCs,体外建立机械划伤致VSMCs增殖模型,采用Cell Counting Kit-8(CCK-8)法检测细胞增殖情况;流式细胞术法测定细胞周期;Western blot法检测p-MEK,p-ERK,Egr-1蛋白表达;Real Time RT-PCR检测MEK和Egr-1 mRNA表达。结果 F2剂量依赖地抑制机械损伤所致VSMCs增殖,降低损伤刺激下VSMCs的生存率和DNA合成,使G0/G1期细胞比例升高,G2/M期细胞百分比下降,并且抑制损伤后VSMCs中MEK/ERK的活化,使p-MEK/ERK蛋白表达降低,同时下调损伤后MEK和Egr-1的高表达。结论 F2对机械损伤所致血管平滑肌细胞增殖有明显抑制作用,其机制可能与影响MEK/ERK/Egr-1信号途径有关。     

TRPV1/SIRT1介导吴茱萸次碱抗AngⅡ诱导的血管平滑肌细胞衰老

目的探讨吴茱萸次碱(rutaecarpine,Rut)对长寿蛋白SIRT1表达及AngⅡ诱导的血管平滑肌细胞(vascular smooth muscle cells,VSMCs)衰老的影响。方法采用AngⅡ(1μmol·L^-1)孵育大鼠胸主动脉平滑肌细胞72 h,预先加入不同浓度的Rut(0.3、1、3μmol·L^-1),采用TRPV1拮抗剂CAPZ(10μmol·L^-1)和AMPK抑制剂Compound C(1μmol·L^-1)探讨TRPV1/AMPK是否介导Rut的保护效应。SA-β-Gal测定衰老细胞数目,DCFH-DA法测定细胞ROS水平。划痕愈合结合Transwell检测VSMCs迁移。Western blot检测VSMCs中长寿蛋白SIRT1和衰老相关蛋白p53、p21的表达以及p-AMPK水平。结果Rut明显地抑制AngⅡ诱导的VSMCs衰老和ROS生成,并抑制VSMCs迁移。预先给予TRPV1拮抗剂可取消Rut这一保护作用。AngⅡ可降低SIRT1的表达,给予Rut可剂量依赖性地恢复SIRT1的表达,且下调其下游衰老相关蛋白p53和p21的表达。AngⅡ可抑制p-AMPK,加入Rut能恢复p-AMPK水平。CAPZ和Compound C可消除Rut升高SIRT1表达的效应。结论Rut可上调SIRT1表达,抑制AngⅡ诱导的VSMCs衰老和迁移,其机制可能激活TRPV1/AMPK信号途径。     

Inhibitory effect of a novel angiotensin II type 1 receptor antagonist RNH-6270 on growth of vascular smooth muscle cells from spontaneously hypertensive rats: different anti-proliferative effect to angiotensin-converting enzyme inhibitor.

The current study was undertaken to evaluate the anti-proliferative effect of a novel angiotensin II type 1 (AT1) receptor antagonist, RNH-6270, on exaggerated growth of vascular smooth muscle cells (VSMC) from spontaneously hypertensive rats (SHR), in comparison with the effects of an angiotensin-converting enzyme (ACE) inhibitor. RNH-6270 and temocapril significantly inhibited basal DNA synthesis in VSMCs from SHRs in a dose-dependent manner, but not in cells from Wistar-Kyoto (WKY) rats. SHR-derived VSMC showed a hyperresponse of DNA synthesis to serum and angiotensin II compared with that of WKY rats-derived VSMC. RNH-6270 did not affect serum-stimulated DNA synthesis in VSMCs from both rat strains. RNH-6270 abolished angiotensin II-stimulated DNA synthesis in VSMC from both rat strains. RNH-6270 significantly inhibited proliferation of VSMC from both rat strains, but the ACE inhibitor temocapril did not exert such an effect. RNH-6270 decreased the specific binding of angiotensin II to VSMC in a competitive manner for angiotensin II receptors in both rat strains. RNH-6270 and temocapril significantly decreased the expression of growth factor mRNAs and proteins in VSMC from SHR, but not in cells from WKY rats. These results suggest that RNH-6270 is a potent AT1 receptor antagonist and has anti-proliferative effects on VSMCs from SHR, which was not seen with an ACE inhibitor. The growth inhibitory effect of RNH-6270 may be associated with the inhibition of growth factors via antagonism to AT1 receptors.